Boston Police Commissioner Ed Davis said Dzhokhar Tsarnaev is in serious condition at a Boston hospital.

Tsarnaev's brother, 26-year-old Tamerlan, was killed early Friday morning in a furious attempt to escape police.

Davis said they received a call from a man Friday night that he noticed blood on a boat in his back yard at 67 Franklin St. in Watertown. The man told authorities when he lifted up the tarp of the boat, he saw Tsarnaev inside. The man immediately called authorities.

Davis said gunshots were exchanged with Tsarnaev, but he is not sure if he was hit with any bullets. He said the blood he was covered in was most likely from wounds he suffered last night.

"We are eternally grateful for the outcome tonight," said Massachusetts State Police Col. Timothy Alben at a news conference Friday night.

"It's a night we are all going to rest easy," said Massachusetts Gov. Deval Patrick.

The stay-at-home ban was lifted Friday afternoon and MBTA trains were put back in service.

Police said the Tsarnaev brothers were involved in the fatal shooting of an MIT police officer on Thursday evening. The officer was identified as Sean Collier, 26.

The brothers also carjacked a vehicle. The vehicle's owner was released unharmed and told police the men told him they were the Boston Marathon bombers.

During the pursuit to Watertown, grenades and other explosives were thrown from the car by the suspects and gunfire was exchanged in the area of Dexter and Laurel streets.

"A bomb went off with a huge cloud of smoke, with another bomb and then it was even more chaos on the corner where they kept firing. And there was a black Mercedes SUV that stormed through the corner and hit a police cruiser. And right after that occurred, I saw a police officer, he had his foot on the dead suspect with the gun pointed at him," said Mike Julakis, who lives on Dexter Avenue in Watertown.

Police were looking for a 1999 green Honda sedan, but now say they have found the car and it is being analyzed.

Who are the suspects?

The Associated Press reported that the brothers were from a region of Russia near Chechnya, and had lived in the United States for an extended period of time.

In a news conference in Maryland, Ruslan Tsarni, the uncle of the brothers, asked his nephew to turn himself in.

"I never, ever would imagine that the children of my brother would be associated with that (the bombing)," Tsarni said.

During the pursuit, a 33-year-old MBTA Police officer was shot and taken to Mount Auburn Hospital in critical condition.

"I can confirm that a Transit Police officer was wounded. He is being treated at this hour at a local hospital," said spokesman Joe Pesaturo. The officer has been on the force for three years and is married with a 6-month-old child.

The Red Sox and Bruins postponed their games Friday evening because of the events taking place on Friday.

A Florida businessman took a photo of the chaos developing after the bombings on Monday.

Little did David Green know at the time that he captured one of the two suspects leaving the scene of the crime.It wasn't until Thursday, when officials released surveillance video of the two suspects, that he realized he had Dzhokhar Tsarnaev, 19, distinctive in his backward white baseball cap, walking away from the scene.

Green said that looking at the photo now, he is struck by two things: Tsarnaev isn't carrying the backpack the surveillance videos show him with before the bombings, and he is acting very differently from everyone around him.